Edwards missed his second straight day of practice on Thursday with a thigh injury. It is the same injury that had Edwards limited the week before the opener, in which he played.
"Yes there is [a concern],'' Rivera said. "He's an older guy. Nagging thing. He was limited as far as running around. What you're hoping for is tomorrow he runs around and tells you it doesn't grab.''
The good news is cornerbacks Josh Thomas (concussion) and Josh Norman (deep thigh bruise) returned to practice on a limited basis. Thomas still hasn't been cleared by doctors to play, but he remains optimistic.
Rivera indicated that if Thomas isn't cleared, Drayton Florence will start at left cornerback. The veteran was among the final cuts in training camp after starting most of the preseason, but re-signed on Wednesday night.
Rivera said strong safety Quintin Mikell and backup running back Kenjon Barner are out for the Giants. He said rookie Robert Lester will start at strong safety with Mike Mitchell moving from strong to free safety to replace Charles Godfrey, who was put on injured reserve with a torn Achilles.